Northern blots of HTK expression in hematopoietic and nonhematopoietic control cell lines (MRC-5 and Hep3B). Poly(A)⁺ RNA (2 μg) was loaded on each lane. The Sma I-Sma I fragment of HTK cDNA (746 bp) was used as a probe. Loading was normalized using a β-actin probe.